All medications manufactured in the US have to have some kind of identifying markings like letters, numbers, logos or a combination of these. Prescription and over the counter medications alike must have markings. However, supplements like vitamins, minerals, herbal products, and any sort of dietary supplements do NOT have to have markings. This makes them much more difficult to identify. If you have a pill with no markings, it is likely a supplement of some kind or it could be manuactured somewhere other than the US or it is an illegally made drug. Even if you were to take it to the pharmacist, it is unlikely that he would know for sure what it is without any identifiers. It would probably be best for you to just dispose of the pill.